Dyeable polyesters



United States Patent 9 2,777,830 DYEABLE POLYESTERS Joseph CloisShivers, In, West Chester, Pa., assignor to E. I. du Pont de Nemours andCompany, Wilmington, Del., a corporation of Delaware No Drawing.Application May 7, 1953, Serial No. 353,688

11 Claims. (Cl. 260-75) This invention relates to fibers, filaments,yarns, films and other structures of new condensation polymers whichhave afiinity for acid dyestuffs. The invention also relates to newfiber-forming condensation polymers which are stable to melt spinningand stable to subsequent processing of the structure, but which areeasily converted into polymers readily dyeable with acid dyestuffswithout substantial loss in physical properties of the structure.

Fiber-forming condensation polymers prepared from polymethylene glycolsand terephthalic acid or esters thereof are attractive polymers. Thesepolymers are eminently suited for melt spinning into filaments which canbe drawn and formed into textile yarns of unusually good properties.However, these yarns and fabrics made therefrom can be dyed at normaltemperatures only with the acetate class of dyestuffs. This limits thefield of usefulness of the fiber. The number of classes of dyes that canbe applied to these yarns may be broadened by modification of thepolymer with basic amino groups so that acid colors may be applied tothe finished yarn. However, attempts to copolymerize dibasic acids orglycols containing the tertiary amino group with polymethylene glycolsand terephthalic acid or esters thereof lead to highly discoloredpolymers having low molecular weights. Furthermore, the use of dibasicacids or glycols containing a primary amino group in polyester formationleads to cross-linked materials which cannot be satisfactorily processedinto fibers, filaments, yarns or films.

Therefore, an object of this invention is to provide a new fiber-formingcondensation polymer which can be readily converted into a polymer whichis easily dyeable. Another object of this invention is to provide atextile yarn, filament, fiber or film of a condensation polymer that iscapable of being dyed with acid colors. Still another object of thisinvention is to provide a new condensation polymer containing a primaryamine. Another object is the provision of a method to convert imidogroups contained in a polymer to primary amine groups. Other objectswill be follows.

The objects of this invention are accomplished by polymerizing linearcondensate polymer-forming ingredi- 1 cuts with a cyclic dicarboxylimidodifunctional compound of the group consisting of dicarboxyl acids, theanhydrides or the esters thereof, or of a diglycol so as to form alinear condensation polymer containing the cyclic dicarboxylimido group.The condensation polymer may be formed by polymerizing the cyclicdicarboxylimido difunctional compound with a dicarboxylic compoundand/or a glycol as with terephthalic acid or one of its esters and/orethylene glycol. While two component polymers can be produced using thecyclic dicarboxylimido compounds of this invention, it is preferred toprepare polymers of three or more components, and, in general, polymerscontaining from about 2% to about 15% of the cyclic dicarboxylimidogroup are most useful. Depending upon the properties desired in theshaped articles, more or less of the imido component will be used. Ingeneral, polymers containing about 0.5% of nitrogen derived from theimido component are produced, for at this level the shaped articles arereadily dyeable. The

apparent from the description that 2,777,830 Patented .Ian. 15, 1957amount of nitrogen may vary from about 0.2% to about 7.5%, depending inpart upon the imido compound used in the polymer preparation.Preferably, the cyclic dicarboxylimido group is attached to anintermediate chain carbon as would result from copolymerizing aphthalimido or 'succinimido compound to give a linear condensationpolymer containing the group,

where X is COO if an imido dicarboxylic compound is used or X is 0 if animido glycol is used; n, m and p may be 0 or an integer from 1 to 20;n+m+p equals at least 2 and is not more than 40; Y is hydrogen oranother cyclic dicarboxylimido group and R is a divalent radical, eitheraromatic or aliphatic in character.

Such polymers are stable at elevated temperatures and may be melt spun.Filaments, fibers, yarns or other structures formed thereof may besubjected to drawing and other aftertreating processes as desired andthen the di carboxyl groups in the imido linkage may be hydrolyzedtherefrom to yield a new polymer readily dyeable with acid colors andcontaining primary amine groups. If desired, hydrolysis of the imidogroups in polymer may be effected prior to drawing with substantiallythe same results. When the dicarboxylimido group is attached to anintermediate carbon of the chain, the polymer will contain the followingstructure after the hydrolysis treatment,

where X is COO or 0; each of n, m and p may be 0 or an integer from 1 to20 and the sum of n, m and p is at least 2 but not fore than 40 andwhere Y is hydrogen, NH2 or a cyclic dicarboxylimido group if hydrolysisis incomplete. The hydrolysis step is not a severe hydrolysis, and thereis no appreciable degradation of the polymer chain. The resultingstructure has substantially the same physical properties as before.

The following examples will serve to illustrate this invention. In theseexamples, which are not limitative, parts are by weight.

Example I A reaction mixture was prepared using 645 parts ofdimethylterephthalate, 650 parts of ethylene glycol (200% excess), 71parts of diethyl alpha-phthalimidosebacate and, as a catalyst, 0.02% ofzinc borate and 0.02% of litharge based on the Weight of thedimethylterephthalate. The reactants were heated to 220 C. atatmospheric pressure in a reaction vessel until the ester exchange wascomplete as evidenced by the cessation of the evolution of alcohol fromthe reaction mixture. The resulting reaction product was then subjectedto vacuum and heated to 260 C. while being suitably agitated. Thepolymerization reaction was continued for 4 hours at an absolutepressure of less than 1.0 mm. of mercury. At the end of this time, thereaction vessel was cooled, causing the polymeric material to solidify.This polymer was light tan in color, had an intrinsic viscosity of 0.68and is believed to have the structure,

SlflGQflfiQlYSlS for nitrogen showed 0.35% while the thephydrazineproduced apolymer containing primary amine retigzl nitrogen contentaccording to this structure is also groups and was readily dyeable witha number of'a'cid 0.3 o. dyes.

Lillie; polyiiier of thisexample was melt-spun? to form, Example IV1,80'dehieryarn co'fn'sis'tin? 05.10 filaments-andwas sub i seqhently;draiivnSS times. In the drawingrzstep a roll heated to:'80(",L'wasinterposed betweenjhe fee d rolls and th draw .rollsoyerwhichthe" yarn was passed to the draw point better and to 'produce more,uniformly; drawn yarn. This yarn" could n t be dyed with acid colors.The physical proper ties of thedrawnyarn were A polymer wasprepardfrolfi 18 parts of dimethylterephthalate, 186 parts-ofethylehgly'col (200% excess) and 20' parts, of diethylalpha-phthalimidosebacate l as describd uh der Example I?Theresulting-polymer cohtained about 5 mol percent-0Ephthalimidosebacataw'as melt spun and drawn into multifilament-yarns'andwas then subjected to hydrolysis for l'hour by means of a 1% solution ofethylene diarnine in ethyLalcohol heated to 78 C. The yarn so" treatedwas readily dyed with an acid dye indicating thepresence of primaryamine as follows: tenacity, 1.7 grams per'd nier'; elongation, 36;denier, 53.

The yarn in the form of skeins walls subjected to the action of a 1%solution of hydrazine in ethanol at a mperatu e at. .3. 1; hm tohydrolyze the grWPS- I V ll fa i 'r f. t i 5 "ly iier; tlirby yieldingxamp piiiyinhr or the fdlltiwiii g 'strilcture; A- olymer drawn yarnprepared from dinlethylterepli' l tli'alate; ethylene glycol and diethylalpha, alpha 1 diphthalilnidosebacat, as" described un'de'r Exaniple'II;

i was subjectedto hydrolysis for 1 hour in aqueous- 1 solution ofethylene dianiine heated to 98 C. Tli'eresulting: yarn" was readilydyahl'e-with acid dyes indicating" theprese'nce of amine-groups.

i l roQd-oonlomowo ortlomhd-oomomo wil This hydrolyzed yalln was'o figood color duality and wasureadily dyeable with a number of aciddyes. 2 Iis furtherlevidence oi the ,presence of primary alpine 5 Example' VIgronn m'ih y e hib d hefpll in P y pmp- A v to k l y l V at l a polymerwas prepared from 19.4 parts of dlmethyl fa s ggi ii i g ggi gggg g i zi trrepll'th'alate, 18.6 parts of ethylene glycol (:20()% excess): outenacity is gas; patellaattracts t 3 Parts} a dlethyllall)hatsvccmilmdqsebacaw i f 53 3 the manner descrlbed in ExamplesAirs-momma as t sultihg olymer showed 0.29 nitrogenwhich cor-re Example"11 spores clo'sley'to the followin'gstructure";

, l a a H A, '0' O O (i NPOIYHier -P p m 1 -4 nililms yllL 11 l l I. ll,.l torephthalatc, 18.6 parts of ethylene glycol ,-QX' l(0Q0-0cmoH:O)n O?H-(CH9rg-oomcmol cess) and 019 part of diethyl alpha;alpha-diphthalimido- N sebacate in the manner disclosedv t nder ExampleI to 0220/ irl lalrq yrn emai n z .at g q. l ants wl I a algam; imsebacate. Nitrogen a alysfigwas 4 GHr-CH:

theoretic";a l nitrogen content of 0.24% based'on 4:0 This polymer wasmelt-spun and drawn lntonlultlfilani ent yarn and as such showed noaflinity for acid dyes. Howfa a itm l the following striict'i'ire,

l l 1 'QC-OoirsoEonFhcn-tomM-om-o-ochronic- Yarn melt-spun from thispolyr'ner and drawn 3.5 times ever, after subjecting a' sample of thisyarn to the actionh properties l r: the y rn of E pl I as did 5 of a 1%solution of ethylene diamine in ethyl alcohol the yarn after. hydrolysisin a hotalcoholic solut onv 9i heated to 78? C; for 1 hour,- the yarnthus hydrolyzed hydrazine." The hydrolyzed polymer contained primary wasreadily dyeable with a number of acid colors indi zirnine groups as wasevidenced by marked aflinity 0f the eating the presence of primary aminegroups. polymer for acid dyes. I I I v Exampl VII l l W Apolymer wasprepared in the manner described in A polymer was p s pfi li'tfi m 11,4pa i s9t igi ty1- Example I using 'diethyl alpha=phthalirnidosebacate asthe terephthalate, l8-6Jpa 1 e lyl nea ycql (?-0Q% F Q sole di'ester andethylene glycol in 200% excess. The and 3.2 parts of diethylalpha-phthalirnidoadipate in the polymer contained 3.75% nitrogen whichcorresponds to rnannrudisclosed in Example I. fI'he p ly er cfintaincdthe calculated nitrogen content for a polymer of the folabout 12%phthalimirdq q pate, groprzs3951, y n y s lowingstrncture,

0 6 5% nitrogenlwas found against a theoretical nitrogen t l 1 r r hinits ba a, mi li itr- The polymer was rig dity n'ielts i abl with utla-lg. mers having up to about 7.5% nitrogen can be -produced. erung.When spun, and drawn into multlfilarncnt yarn, ygfimfi Vi l Hydrolysisof the yarn in a hot alcoholic solution of Amino glycols (e. g.13-ansinopentaeosane L 25-d iol) th cyarn properties were ofthe orderpreviously set for canbe converted to the phthalimidoderivative'byfieaction with phthalic anhydride asfollows:

The anhydride reacts preferentially with the amino group. The resultantphthalimido glycol can be reacted with a dicarboxylilc compound, such asterephthalic acid, sebacic acid; adipicacid and similar acids, with orwithout additional glycol to form condensation polymers containing thephthalimido group, Similarly, other phthalimido glycols, such as7-phthalimidotridecane-1,l3- diol or l2-phtha imidotricosane-1,23-diolmay be prepared and reacted in the manner herein described to formcondensation polymers containing the phthalimido group. Such polymersare not dyeable with acid colors, but they are altered by hydrolysis toprovide primary amine 'groups in the polymer structure and thesepolymers arereadily dyeable with acid colors.

Example IX Oximino diestersare also converted to phthalimido diesters bythe following synthesis:

involved in cols may-be compounds having the structure Other x methodsand systems of con'clen'sation polymerization may be used than thoseshown in the examples of this invention as will be readily apparent toone skilled in the art. Also, other polymerizing reactants may beaddition to the primary chain 'forming ingreclients and the compoundcontaining the cyclic dicarboxylimido group.

Instead of 'or alongwith ethylene glycol, there may be used polyglycolssuch as polyethylene glycol. Such glypresent, hydrolysis may beadvantageously carried out with a hot alcoholic solution of hydrazine.Alcoholic or aqueous solutions'of ethylene diamine'arealso es-,peciallyuseful in maintaining good properties inthe struc- "ture' whileefiectively" removing the cyclic dicarboxyl group. Usually, the dibasicacid component of the imido residue is completely removed, but notnecesarily so. Further, all of the imidoresidues need not be convertedOOzOzHs 00202116 0 (|C':H5 3 out). 2 (out). i, (EH91 C=NOH BIC-NH: 0 HoN 0H2). (cm). ((5 91 COzOaHs 00202115 COsUaHs In the described reactionsof this example x=y=6 or 11, but other values may be given to x and y aswill be apparent to one skilled in the art. The phthalimido diesters maybe reacted witah glycol, with or without additional diester to formcondensation polymers containing the phthalimido group. Although suchpolymers are not dyeable with acid colors, they are converted byhydrolysis to polymers provided with primary amine groups which arereadily dyeable with acid colors.

In the cyclic dicarboxylimido group it o=0 c=0 R represents a divalentradical, for example, ethylene group, 1,2-propylene group, 1,2-phenylenegroup or said groups substituted by one or more alkyl, alkoxy, phenyl orthe like. In the aliphatic imido derivatives, it is preferred that inthe R group the carbon atoms adjacent to a carbonyl group bear at mostonly one such substituent. The free bond of the nitrogen is attached toan inner chain carbon of a dibasic acid or the anhydride or esterthereof, or of a glycol so that this modifying compound may take part inany of the usual condensation polymerization reactions. Among the usefulcondensable diacids or the anhydrides or diesters thereof, containingthe cyclic carboxylimido group, besides those of the examples arediethyl alpha-phthalimidoglutarate, alphaphthalimidoglutaric anhydride,dimethyl alpha-phthalimidosebacate, dimethyl alpha-phthalimidoadipate,dimethyl 2-(N-phthalimidomethylene) terephthalate, dimethyl alpha,alpha'-diphthalimidoadipate, diethyl alphasuccinimidoadipate, dimethylalpha-phthalirnidosuberate, diethyl alpha-phthalimidopimelate, diethylalpha-phthalimidoazelate, diethyl alpha-glutarimidosebacate, diethylalphatetrahydrophthalimidosebacate and similar compounds.

II o to amine groups. It is preferred, however, to remove the imidoresidues completely, for the best dye afiinity is produced by so doing.

By means of this invention, condensation polymer structures acquireimportant aflinity for acid dyes and without sacrifice of desirableproperties of the structure. The polymerization proceeds smoothly andwith the production of a high quality polymer, which polymer may bemelt-spun or otherwise subjected to high temperature shaping withoutdegradation of the polymer. After the need for subjecting the polymer tohigh temperature is passed, the chemical structure of the polymer may bereadily altered, either before or after drawing, to free the primaryamine group and thus confer acid dye atfinity to the structure.

Any modification which conforms to the principles of the inventiondescribed herein is intended to be included within the scope of theclaims below.

I claim:

1. A shaped article prepared from a linear fiber-forming polymericdicarboxylic acid-diglycol ester by a hotmelt extruding process, thesaid polymeric ester having an imido side group which upon hydrolysiswith hydrazine is converted to an NHz group, and is then dyeable withacid dyes.

2. A polymeric ester in accordance with claim 1 which contains fromabout 0.2% to about 7.5% nitrogen} 3. A polymeric ester in accordancewith claim 1 which contains about 0.5% nitrogen.

4. A linear polymeric ester fiber prepared by hot-melt spinning, saidpolymeric ester containing the group where in X is selected from thegroup consisting of t ll Q 0 and -O-; each of n, m and p is an integerwith a value 7 between zero and 20, providing their sum is at least 2and not more than 40; Y is selected from the group consisting ofhydrogen and a cyclic dicarboxylimido group; and R is a divalentradical, the cyclic imido group being convertible to NH; by hydrolysiswith hydrazine.

5. A polymer in accordance with claim 4 wherein X 7. A polymer inaccordance with claim 4 wherein X is o l; O Y is hydrogen; R is a1,2-phenylene group; n and p are each zero; and m is 2.

8. A process for the conversion of acyclic dicarboxylimido groupcontained in a polymeric ester to an amino group which comprisestreating said polymer with an agent selected from the group consistingof ethylene diamine and hydrazine, and thereafter dyeing the saidpolymeric ester with an acid dye.

9. A process in accordance with claim 8 wherein said agent is hydrazine.

10. A process in accordance with claim 8 wherein said agent is ethylenediaminc.

11. in the process of preparing filaments of a linear polymeric esterdyeable with an acid dye, the steps which comprise forming at least oneimido group on a side chain of the polymeric ester, hot-melt spinningthe said polymeric ester containing the imido groups to form a filament,drawing the same, and converting the imido nitrogen to an NHz group.

References Cited in the file of this patent OTHER REFERENCES Sprung: J.A. C. 8., vol. 61, pp. 3381-85, Decemher 1939.

Reynolds et al.: J. A. C. 8., V01. 69, p. 911 et seq., April 1947.

1. A SHAPED ARTICLE PREPARED FROM A LINEAR FIBER-FORMING POLYMERICDICARBOXYLIC ACID-DIGLYCOL ESTER BY A HOTMELT EXTRUDING PROCESS, THESAID POLYMERIC ESTER HAVING AN IMIDO SIDE GROUP WHICH UPON HYDROLYSISWITH HYDRAZINE IS CONVERTED TO AN NH2 GROUP, AND IS THEM DYEABLE WITHACID DYES.